In the semiconductor industry, various processes can be used to deposit and etch materials on wafers. Deposition techniques include processes such as electrochemical deposition (ECD) and electro chemical mechanical deposition (ECMD). In both processes, a conductor is deposited on a semiconductor wafer or workpiece by having electrical current carried through an electrolyte that comes into contact with the surface of the workpiece (cathode). The ECMD process is able to uniformly fill the holes and trenches on the surface of the workpiece with the conductive material while maintaining the planarity of the surface. A more detailed description of the ECMD method and apparatus can be found in the U.S. Pat. No. 6,176,992, entitled “Method and Apparatus For Electro Chemical Mechanical Deposition”, commonly owned by the assignee of the present invention.
If a conventional plating process is performed to deposit the conductive material in a deposition chamber, the workpiece may be transferred to another chamber in the cluster tool for chemical mechanical polishing (CMP). As is known, the material removal can also be carried out using electrochemical etching by making the workpiece anodic (positive) with respect to an electrode after completing an ECD or ECMD process.
Regardless of which process is used, the workpiece is next transferred to a rinsing/cleaning station or module after the deposition and/or polishing steps. During the rinsing/cleaning step, various residues generated by the deposition and/or polishing processes are rinsed off the workpiece with a fluid such as de-ionized water or de-ionized water with small amounts of other cleaning and/or passivating agents, and subsequently the workpiece is dried.
Conventionally, processing chambers are designed in multiple processing stations or modules that are arranged in a cluster to form a cluster tool or system. Such cluster tools or systems are often used to process a multiple number of workpieces at the same time. Generally, cluster tools are configured with multiple processing stations or modules and are designed for a specific operation. However, in such conventional cluster tools, deposition and cleaning processing steps both typically require separate chambers. For this reason, in known cluster tools, for a workpiece to be processed and cleaned, it must be moved to another station or system. Thus, such configured systems require picking workpieces from a particular processing environment and placing them into a cleaning environment. The workpiece can be cleaned and dried in a cleaning and a drying module using, for example, a rinse and spin process, as known in the art.
When the workpiece is transferred to the cleaning and drying module, contaminants may have attached themselves on the workpiece surface. The source of these contaminants may be the plating/polishing agent, transferring mechanism, surrounding air, the processing facility, personnel, process chemicals, and the like. The workpiece surface should be free of such contaminants; otherwise, the contaminants may affect device performance characteristics and may cause device failure to occur at faster rates than usual.
The speed of which the workpiece is transferred from one module to the next is also critical. As is well known in the semiconductor industry, the production line for manufacturing the workpiece from beginning to end must be performed in the most efficient manner.